Genetic Testing Shown to Improve IVF Success [Updated]

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Update, 6 August 2018. Results of a randomized multi-site clinical trial reported today show pre-implantation genetic tests for PGT-A do not increase the rate of live births among women age 36 to 40.

2 August 2018. A recently published study shows a genetic test for abnormal number of chromosomes conducted with women seeking to become pregnant helps improve their chances for in-vitro fertilization success. The study, published in the 1 July issue of the journal Fertility and Sterility, assesses a pre-implantation screening service offered by Natera Inc., a genetic testing company in San Carlos, California.

Natera offers genetic tests to screen for inherited diseases. The company says its tests analyze an individual’s DNA to the level of single nucleotide polymorphisms, or SNPs, the most common type of genetic variation. SNPs are numerous and found throughout a person’s DNA, but when they occur in a gene or a region of genes associated with disease, SNPs can affect the functioning of those genes and thus be indicators of disease. Natera says it supplements routine genetic tests with statistical tools that enable the company to separate real results from background noise that can otherwise interfere with interpreting the data.

One of Natera’s services, known as Spectrum, is designed for women considering in-vitro fertilization to aid in becoming pregnant. The test screens for aneuploidy or PGT-A, a mutation that results in a greater or lesser number of chromosomes than the normal 24. The test typically takes a biopsy of embryonic tissue on day 5 or 6 of development, and before an embryo’s implantation. Natera says Spectrum can reduce the chance for miscarriage, particularly among older women of maternal age who become pregnant and are more likely to have aneuploidy.

The study, conducted largely by Natera executives and staff, reviewed the records of 974 women who took part in in-vitro fertilization, or IVF, at clinics in San Francisco and Littleton, Colorado over a period of nearly 4 years. The women, age 20 to 46, underwent a total of more than 1,800 in-vitro fertilization cycles, or egg retrieval and thaws. The Spectrum tests showed a rate of aneuploidy of 43 percent for the women overall, with rates ranging from 27 percent for those under 35 to at least 70 percent for women over 40 years of age.

Among women completing embryo transfers, the results show high success rates for implantation and pregnancies, and across age categories in most cases. Some 7 in 10 embryos (70%) were successfully implanted, with 71 percent becoming pregnant. About 5 percent of women overall experienced miscarriages, although the rates were higher for women over 40. Among this group, 65 percent had live births, with small variations among age categories. Natera says in the U.S. today, less than half of in-vitro transferred embryos are successfully implanted and lead to pregnancies.

“This study shows that Spectrum PGT-A can help mitigate the negative effects of maternal age on IVF outcomes by allowing selective transfer of embryos that are more likely to lead to sustained implantation,” says Kimberly Martin, Natera’s senior medical director for women’s health in a company statement. “These findings also demonstrate that successful IVF can be achieved without multiple-embryo transfer when combined with PGT-A. Increased use of single embryo transfer should reduce the incidence of multiple pregnancies, which are associated with higher pregnancy complication rates, in addition to financial and psychosocial challenges for families.”

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